Single photon emission computed tomography (SPECT) has become an invaluable tool in diagnosis and medical research. An experimental program is proposed to carry out a feasibility study of a novel high sensitivity and high resolution SPECT instrument. The energy and spatial resolutions of the proposed detector are expected to be improved by factors of 6 and 2, respectively. The proposed detector win measure the direction of the incident y-ray hence eliminating the need for a collimator. The high angular resolution and wide aperture enables detailed imaging of the large organs of the human body for medical, biological and chemical investigation. Good energy resolution will enable discrimination of natural and scattered gamma-ray background with higher effectiveness than available at present. High sensitivity (greater than 100 times available at present) permits fast imaging in only 10 to 30 sec and opens the way for real time metabolism visualization. The detector can be designed for single head with curved surface or formed into a cylindrical detector to image the body or the brain without the need for rotation. The proposed instrument is expected to have smaller size and substantially lower weight than Anger cameras used at present. It also has good potential to be used for medical diagnosis in the field. Preliminary Monte Carlo calculation which stimulate a generic system demonstrate the potential of the proposed SPECT. Phase I of this proposal involves Monte Carlo simulations and the design, assembly and testing of a small desktop prototype to demonstrate the feasibility of the proposed design. During Phase II a functional prototype SPECT instrument will be built.